1. Field of the Invention
The present invention relates to an adjustable piston having variable compression height which may be changed in response to a command from an engine controller.
2. Disclosure Information
Variable compression ratio pistons have been the subject of many designs U.S. Pat. No. 3,403,662 to Blackburne, U.S. Pat. No. 3,418,982 to Waugaman, U.S. Pat. No. 3,450,112 to Bachle, U.S. Pat. No. 4,138,973 to Luria all disclose systems for variable compression ratio pistons in which the height of the piston is responsive to pressure within the combustion chamber Such pistons suffer from the deficiency that they are not controllable by signals other than the pressure within the combustion chamber.
U.S. Pat. No. 3,200,798 to Mansfield discloses a piston having a pump driven by an eccentric formed upon the small end of the connecting rod for the purpose of providing pressurized oil for changing the compression height of a piston. As before, the piston is not capable of responding to a control signal other than combustion chamber pressure.
U.S. Pat. No. 4,785,790 to Pfeffer et al. discloses a variable compression height piston having special valving which allows additional oil to flow into the upper control chamber of the piston so as to increase compression ratio while the engine is being started.
U.S. Pat. No. 4,979,427 to Pfeffer et al. discloses a thermally responsive variable compression ratio piston.
U.S. Pat. No. 4,469,055 to Caswell discloses a variable compression ratio piston having a remotely controlled pump and a sensor network which provides hydraulic Pressure through a flexible line to the piston. It is not believed that such a system would be durable in a modern high speed engine because of the need to accommodate the flexible duct between the pump and piston.
U.S. Pat. No. 4,809,650 to Arai et al. discloses a variable compression ratio piston which is responsive to a control pressure coommunicated by a channel formed within a connecting rod. The piston disclosed in the '650 patent is capable of operating at only two controlled positions--i.e., maximum compression height and minimum compression height. It is not possible to position the piston in intermediate compression heights.
It is an object of the present invention to provide a variable compression ratio piston which is positionable in a plurality of compression heights from a maximum to a minimum value.
It is an object of the present invention to provide a variable compression ratio piston which will allow adjustment of a piston's compression height to optimize engine operation not only for high speed high load operation but also for cold starting.
It is yet another object of the present invention to provide a variable compression height piston which may be controlled with either a hydraulic signal communicated through the normal oil passageways of an engine, or by means of an electronic device within the piston.
Other objects, features and advantages of the present invention will be apparent to the reader of this specification.